Creating Exposed Trusses in a Cathedral Ceiling

Reference Number: KB-00416Last Updated: 12-19-2014 09:04 AM

The information in this article applies to:

QUESTION

How can I create exposed roof trusses in a room with a cathedral ceiling?

ANSWER

When a roof ­truss is drawn in Chief Architect, the program locates a roof plane to define the top chords of the truss, and a ceiling plane to define the location of the ­bottom chord. You can create exposed trusses by creating a ceiling to define where you want the trusses' bottom chords, drawing the trusses, and then removing the ceiling.

To set up the structure for exposed trusses

Open the plan file in which you would like to create exposed roof trusses.

In this example, a simple rectangular structure is used.

If your plan has multiple floors, go up to the floor where you want to create exposed trusses.

Select Edit> Default Settings from the menu. Select Floor from the list and click the Edit button. On the Structure panel of the Floor Defaults dialog for the current floor:

Specify the desired ­top plate height for your bearing walls as the Rough Ceiling height, then click OK. This will also be the height of your roof truss bottom chords in a standard truss.

Specifying the Ceiling height in the Floor Defaults dialog will affect all rooms set to use the default on the current floor. If you want to modify the Ceilingheight of only one room in your plan, you can do so on the Structure panel of the Room Specification dialog.

In the Default Settings dialog, select Framing from the list and click the Edit button.

In the Framing Defaults dialog:

Go the Trusses panel and specify the desired Member Depth and Maximum Horizontal Span for your trusses.

In this example, the Depth values are set at 8" and the span values are unchanged.

On the Roof panel, specify the desired truss width in the Rafter Width text field.

Click OK to close the Framing Defaults dialog, then click Done to close the Default Settings dialog.

Select Build> Roof> Build Roof from the menu. In the Build Roof dialog:

Check Build Roof Planes on the Roof panel

Also on the Roof panel, check Trusses (No Birdsmouth);

Specify the desired Pitch and other attributes of the roof;

Click OK to close the dialog and build the roof.

Make any needed modifications to the ceiling to produce truss bottom chords that meet your needs. For example,

Use the default flat ceiling to produce a standard truss:

Raise the ceiling height of a room to produce a modified truss with a raised bottom chord (make a note of the original value before doing so):

Remove the default flat ceiling and draw sloped Ceiling Planes to produce a ­scissor truss. More on creating scissor trusses can be found in the Related Articles section at the bottom of this article.

In Chief Architect X3 and later, you can specify a room's ceiling structure: for example, 5/8" ­sheetrock with a covering of paint, or a single layer of planking or ­tongue and groove. See the Related Articles section for more information.

To draw the roof trusses

Select Build> Framing> Roof Truss from the menu, then click and drag a line over the roof to create a single roof truss.

Move the truss into position over a non-bearing wall either using its edit handles or by moving it using a dimension line.

With the first truss in place over an exterior wall, click on it to select it, then click the Multiple Copy edit button.

In Home Designer Pro, use the Transform/Replicate Object edit tool to make copies of the trusses.

Next, click the Multiple Copy Intervaledit button to open the Multiple Copy dialog:

Specify the desired Offsets Between Copies When Dragging for All Trusses and click OK.

When you click OK, the truss will still be selected and the Multiple Copyedit tool will still be active.

Click and drag the truss perpendicular to itself using the Move edit handle to create copies of the truss at the specified intervals. As you drag, your cursor will display the Multiple Copy icon.

When you have the desired number of trusses, release the mouse button.

To make the trusses exposed

When your trusses are in place, click the Select Objects tool, select the room below the trusses and click the Open Object edit button.

On the Structure tab of the Room Specification dialog:

Under the Ceiling heading, remove the checkmark beside Ceiling Over This Room.

If you changed the Ceiling height value to produce a modified truss, restore the value that you made a note of in step 5, above.

Click OK to close the dialog and apply your changes.

Select 3D> Create Perspective View> Full Camera from the menu, then click and drag a camera arrow inside the room with the trusses above.

Scroll down to the Framing, Roof Trusses layer and click in the Disp column to place a checkmark in that column.

Click OK to close the dialog and apply your change.

If you would like the top chords of your trusses to be exposed, click on the roof planes above to select them, then click Open Object edit button. On the General panel of the Roof Plane Specification dialog:

Lock the pitch by clicking the radio button to the right of the Pitch text field.

Increase the Baseline Height by typing in the text field. The height that you specify may depend on the Ceiling Finish that you specified above. For example:

If you specified planking, you may want roof planes that bear entirely on the trusses and should raise the Baseline Height by an amount equal to your trusses' ­top chord depth.

If you specified sheetrock, you wouldn't want the sheetrock to bear on the trusses, and might increase the Baseline Height by the top chord depth minus the sheetrock thickness.

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